Automatic stop for phonograph-records.



S. G. ALEXANDER. AUTOMATIC STOP FOR PHONOGRAPH RCORDS.

APPLICATION FILED Niki-5.191?- Patented Sept 18, 1917.

w m E V. N I

WITNESSES:

S/ze; mm Mlemrzder SHE-BEAN G. ALEXANDER, OF ST. LOUIS, MISSOURI.

AUTOMATIC STOP FOR PHGNOGRAPH-RECOBDS.

Specification of Letters Patent. Paitented Sept. 18, 1917.

Application filed January 15, 1917. Serial No. 142,446.

To all whom it may concern Be it known that I. Sneniux G. ALEX- AXDER. a citizen of the l'nited States, resid ing at St. Louis. State of Missouri, have invented i'tfllillll new and useful Improvements in .intonnitii: Stop for lhonograph- Records. of which the following is a full rleur. and eA'Llt'i. description. reference being bad to the acronipunying' drawings, forming a part hereof.

My invention has relation to improvements in automatic stops for phonograph recto-(l and it consists in the novel features of construction more fully set forth in the specification and pointed out in the claims.

The object of nrv invention to provide an automatic top fol phonograph records which will arr st the rotation of all record disks when the end of the record has been reached bv the stylus. irrespective of the length of the record and withoui regard to the radial distance of the inner terminal of the rec rd from the rotation axis of the disk. The present stop device thus susceptible of universal application to all records be the latter long: or short, or be the same impressed on a large or sinnll disk, the stop differing in this respect from prevailing automatic stops whi h must be adjusted to each individual. record to make the same effective. The advantages of the present invention will be fullv apparent from the following: dctuiled description in connection with the acvoinpanying drawings in which-- Figure 1 represents a side elevation of a disk sound rcproducer showing the applicution of my invention thereto; Fig. 2 is a top plan thereof; l 1g. 3 is an enlarged plan of the brake mechanism for the platfornr carrying the record dish; Fig. 4 is an edge view of the parts shown in Fig. 3; and Fig. 5 is a diagrannnatic illustration of the inner circle of the record. terminating close to the center of the disk in conjunction with the high pitch spiral extension of the inner circle of a record terminating at a greater distance from the center of the disk.

Referring to the drawings, 1, represents a hollow bracket arm to the upper end of which is swiveled the tone arm Q'terminatmg in the goose-neck or sound-box tube 3, the short arm of the goose neck leading to the reproducer 4 which supports the needle or stylus 5. The arm 1 is supported by the vertical wall of the sound chamber or box 6 above which is inoun-ted the platform 7 carrying the record disk 8, said platform being provided with a marginal depending flange a. all as fully understood in the art.

Mounted pivotally about a stud t at one end of a supporting plate 9 on top of the box 6 below the platform 7 is a brake arm 1 terminating in a brake tip 11 of soft. material such as rubber. leather and the like. said tip operating to engage the inside of the flange II when the brake is applied. Formed with the hub 12 of the brake is a bracket 13 to which is hinged the brake lever 14 whose short arm when the lever is in normal position omit rest is shouldered to the member 13. being held in said normal position by the flexed spring 15 hearing against the side of the lever, the fixed end of the spring being secured to the member 13. As shown to best advantage in Fig. 4, the brake 10 is oilsi-t from the hub 12 so as to bring the tip 11 in the plane of the flange a of the platform 7. Mounted pivotally about a stud t at the opposite end of the plate 9 is a trigger lever 16 whose free end is provided with a forwardly projecting toe-piece 17 adapted to enter a notch n in the hub 12 of the brake arm, the said toe piece being drawn into said notch as presently to be more fully described. by the action of the contractinn spring 18 one end of which is secured "i bracket or lug 1-) on the lever-16 and the other end to :1 lug 20 on the bracket, 13 leading from the hub 12.

Depending from the tone arm 2 above the box 6. is a tappet or pin 21 whose arc of 0scillation lies in the path of sweep of the outer end of the brake lever 14, the function of the tappet being to actuate the members 1-1 and 10 in proper direction to rotate the hub 12 sufiiciently to bring the notch 12. into engagement with the too 17 as more fully explained later on. The trigger 16 is provided with a lever arm 16' disposed at an angle thereto, the member 16, 16', constituting virtually a bell-crahk of which the member 16 is the shorter arm.

As well understood in the art, the records are in the form of spiral grooves starting at the outer margin of the record disk and gradual}?! approaching the center of the disk, di erent records terminating at difl'tr ent radial distances from the centers of the disks. Some records terminate at a short radial distance from the center as for cxample at the outer terminal of a radius do scribing a small circle 1' (Fig.5). Others device must be set for each record in order.

that the disk carrying that record may he ar rested in its rotat ion when the needle reaches the inner terminal of the record. The object of my invention is to dispense with this individual adjustment, my improved stop being universally applicable to any re ord irrespective of the radius of the circle along I which the inner end of the record terminates.

,In my invention when the stylus reaches a given point on the disk, such disk will come to a stop. it being understood however that this point corresponds in position to the outer terminal of a radius describing the smallest circle by which the inner end of the record is defined. In records which terminate outside of such innermost point, I

rori le a high pitch spiral groove 5 formmg acontinuation or extension of the record groove which happens to terminate along a circle of larger diameter (7" than the smallest circle (r) above referred to, the action of such spiral being fully explained in the description of the operation of the device said operation being substantially as follows: In starting a record it is of course necemary to swing the tone aim outwardly so as to bring the stylus into the outer terminal of the record groove. In Fig. 2 the (enter line of the tone arm for the starting position is indicated by the letter In starting, the lever It is oscillated snfliciently to bring the notch n of the hub 12 of the brake 10 opposite the toe-piece 1T whereupon the spring 18 draws the tocpiece into the notch. the parts assuming the position shown in Fig. :2. The driving mechanism in the box 6 now starts to rotate the platform 7 and disk 8 as indicated by the arrow in Fig. '2 the stylus being caused to traverse the spiral groove of the disk until the inner end of the record groove on the circle 2'' is reached, after which the stylus continues along the high pitch spiral groove 2 until it reaches the point h (Fig. 5). By this time the tappet 21 on the tone-arm w'ill have engaged and tripped the arm 16 of the trigger 16 causing the latter to oscillate anim l-div and withdraw the toe 17 out of the notch n. This lea es the hub 12 of the brake 10 free to rotate about its axis under the contracting action of the spring 18 causing the notch n to be rotated away from the toe 1i and causing the brake arm 10 with its brake tip 11 to oscillate to ward and against the fla'nge a of the plat.- form 7 and thus a resting the said platform and disk 8 carried thereby in their rotation. The released position of the parts controlled by the trigger 16 is shown in Fig. 3. If the inner end of the record happens to terminate on the smallest circle such as r (Fig. 5) when the stylus reaches the point h the machine will come to a stop as already dexazribed. It will be observed that the point Il- Fig. 5) corresponds to a point on a disk the inner terminal of whose record is defined by the smallest ciliclew', said point it being at the intersection of? such c rcle 1- with the spiral extension 8 leading from the inner terminal of a record defined by any larger circle such as r. If the record terminates for example in the larger circle r, the needle'continues along the high pitch spiral s, and when the point It is reached, the arm 16' is tripped. the brake 10 is released and applied to the flange :1 of the platform T. If on the other hand the record inserted into the machine happens to be one whose inner end terminates at a point on the smallest circle r such a record need not be provided with a spiral 8, because when the stylus 5 reaches the point It on such smaller circle the machine will come to a stop. In other words, the spiral a is marked onl on those disks whose records terminate a ong circles (1") which are larger than the smallest circle r at which the records of revailing 0n the market terminate. he spiral s is inert, that is to say it is not translatable into sound as is the case of the grooves forming the record. when the stylus passes over it. It however forms an element in the stop mechanism being that it directs the stylus to the int it, this point being reached concurrent y with the impact of the tappet 21 against the lever 16 when the trigger 16 is tripped to release the brake 10. In some instancm and for record disks of large diameter the tone arm 2 might have to be swu to bring its center line along the line 2 2) that. is to say past the lever 14. For this reason the said lever is hinged to the bracket 13, the weak spring 1-3 permitting the lever to yield to allow the tappet 21 to sweep past the lever with a return movement of the tone-arm. After the tappet has pamed the lever the spring restores the latter to its normal p0- SltlOIl (Fig. 3). The device may of course be modified in many particulars without dc parting from the spirit of the invention; and while here shown in connection with a sound reproducer. it may with equal propriety be applied to sound recorders.

From the foregoing it will be seen that all records are caused to stop when the stylus reaches a point corresponding to the point It in recoros tcrmina cle (r). Where they terminate on a larger circle (1" the high itch spiral a quit: ly brings theneedleto tpointrmthes p' correspondingtothepointhsothatahrwmthemnallcstcin ords stop when the stylus reaches a predetcrmine distance from the center or rotation axis of the disk. No adjustments are necessary for individual disks.

Having described my invention what I claim is:

1. In combination with a rotatable record disk provided with a translatable stylusg'uidi v spiral record, a hrake'for locking the dis against rotation, a trigger for hold-1 ing the broke in released position during the translation of the record a lever hinged to yield in one direction leadin from the brake and operating to throw their-eke out of engagement with the disk with a movement in the opposite direction, and a movable member forming an element of the translating mechanism for tripping the trigger from engagement with the brake to permit the latter to arrest rotation of the disk when the stylus has reached the end of the record.

2. In combination with a rotatable flanged platform and record disk secured thereto, a tone-arm oscillating across the disk and carrying a stylus traversing the disk record, an oscillating brake adapted to engage the flange of the platform, a brake lever leading from said brake and hinged to yield in one direction in response to the 'movement of the tone arm, a hub at the base of the brake provided with a notch, an oscillating trigger providcd with a toe engaging sai notch (luring the sweep of the tonearm with the traverse of the stylus along the record, an arm leading from the pivotal end of the trigger, a contracting spring connecting the trigger and brake arm operating to rotate the hub to bring the notch out of the Way of the toe and simultaneously applying the brake upon Withdrawal of' the toe from the notch, and a tappct on the tone-aim operating to strike the lever leading from the trigger and cause the lever to trip the trigger to withdraw the toe from the notch, the parts operating substantially as and for the purpose set forth.

3. In a stop mechanism for record disks, an oscillating brake member, a brake lever leading therefrom and hinged to yield in one direction, and a flexed spring for re storing said lever .to normal position.

In testimony whereof I affix my signature, in presence of two witnesses.

SHERMAN G. ALEXANDER \Vitnesses:

EMIL S'ranmr, Jos. A. MICHEL. 

